import type { HydrogenOverviewResponse } from '../api';

export function formatKg(kg: number): { value: string; unit: string } {
  if (kg >= 1000) return { value: (kg / 1000).toFixed(2), unit: 'T' };
  return { value: kg.toFixed(2), unit: 'Kg' };
}

export function formatYuan(yuan: number): { value: string; unit: string } {
  const absolute = Math.abs(yuan);
  if (absolute >= 100_000_000) {
    return { value: (yuan / 100_000_000).toFixed(2), unit: '亿元' };
  }
  if (absolute >= 10_000) {
    return {
      value: (yuan / 10_000).toLocaleString('zh-CN', { maximumFractionDigits: 2 }),
      unit: '万元',
    };
  }
  return {
    value: yuan.toLocaleString('zh-CN', { maximumFractionDigits: 0 }),
    unit: '元',
  };
}

export function formatRelative(timestamp: number, now = Date.now()): string {
  const seconds = Math.max(0, Math.floor((now - timestamp) / 1000));
  if (seconds < 5) return '刚刚';
  if (seconds < 60) return `${seconds} 秒前`;
  const minutes = Math.floor(seconds / 60);
  if (minutes < 60) return `${minutes} 分钟前`;
  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${hours} 小时前`;
  return new Date(timestamp).toLocaleString('zh-CN', { hour12: false });
}

export function formatRefreshTime(timestamp: number, now = Date.now()): string {
  const exactTime = new Date(timestamp).toLocaleString('zh-CN', {
    year: 'numeric',
    month: '2-digit',
    day: '2-digit',
    hour: '2-digit',
    minute: '2-digit',
    hour12: false,
  });
  return `${formatRelative(timestamp, now)} · ${exactTime.replace(/\//g, '-')}`;
}

export function deriveOverviewMetrics(data: HydrogenOverviewResponse) {
  const { kpi, monthly, stations, top5 } = data;
  const monthAvgKg = monthly.length > 0
    ? monthly.reduce((sum, month) => sum + month.kg, 0) / monthly.length
    : 0;
  const bestMonth = monthly.reduce<typeof monthly[number] | null>(
    (best, item) => (!best || item.kg > best.kg ? item : best),
    null,
  );
  const latestMonth = monthly[monthly.length - 1];
  const previousMonth = monthly[monthly.length - 2];

  return {
    monthAvgKg,
    bestMonth,
    latestMonth,
    monthMomentum: latestMonth && previousMonth && previousMonth.kg > 0
      ? ((latestMonth.kg - previousMonth.kg) / previousMonth.kg) * 100
      : null,
    top5Share: (top5.reduce((sum, item) => sum + item.kg, 0) / Math.max(1, kpi.yearKg)) * 100,
    profitYield: kpi.yearRevenue > 0 ? (kpi.yearProfit / kpi.yearRevenue) * 100 : 0,
    stationAvgKg: stations.length > 0 ? kpi.yearKg / stations.length : 0,
    monthlyDual: monthly.map(month => ({
      ...month,
      monthLabel: `${month.month.slice(5).replace(/^0/, '')}月`,
    })),
  };
}